2004AJ....128.1847J

We present new multiband photometric results for 29 ROTSE-I δ Scuti stars and a Fourier decomposition light-curve analysis in order to reclassify their variability types. For the classification between eclipsing and pulsating stars, we use the criterion that pulsating stars have larger amplitude differences between passbands than eclipsing binaries, because the brightness changes in pulsating stars are mainly due to variations in temperature. From this investigation, we find that 24 of our 29 observation targets are W Ursae Majoris type eclipsing binaries. Fourier analysis of the data for all 91 ROTSE-I δ Scuti stars shows that the phase parameters φ₂₁of the high-amplitude δ Scuti variables identified in this study are concentrated around 4.0. This high-probability area characterized by φ₂₁is in good agreement with the finding from OGLE data. Our results suggest that most of the ROTSE-I δ Scuti stars located outside the high-probability area are in fact W UMa type eclipsing binaries.